Arrangement in rectifiers for electric alternating currents.



i. F, G. P, HARTMANN ARRANGEM-Em 1N REGTIFIERS FOR Hmmm AUERNANNGCURR'EMS.

JLIUS FREDERIK GEORG POUL HARTMANN, 0F CGEN'HAGEN, DENMARK.

RRANGEMENT IN BECTIFIEBS FDR ELECTRIC ALTERNATING CURRENTS. 4

Specification of Letters Patent. l Patented Nov, 18, 1919,

Application iiled March 7, 1919. Serial No. 81,277.

a rectiiier for electric currents consisting of.

one or more conducting liquid jets, generally mercury ]ets, which passthrough a magnetic field perpendicular' to the direcytion of the jet.and strike an electrode.

Through the interaction between current and field, waves are formed onthe jet which move forward at the speed of the particles of the jet, andthe place at which the jet brthe jet-s strike the electrode orelectrodes sometimes'divided by insulating partition walls, is therebycaused to move over the electrodein such a manner that the desiredrectication is effected.

In the said rectiers the intensity et the rectified current iseterniinative of the height of the Wave formed on the jet. Corrsequehtly the intensity of the rectified current must not decrease undera cert-ain limit, as 'a regular rectification demands that the Waveshould not become smaller than a certain size. In a rectifier with aplurality of iets it is possible to regulate tlf@ intensity of thecurrent downward from the maximal value by setting out of activity moreor less jets; but where only one single jet is found, the regulation israther limited# l.

A. regulation ot the intensity of the field, whereby the same isaugmented in relation to the decreasing ot the intensity of current israther diiiicult to eect automatically and is practically only possiblewithin certain limits, as it is not possible to continually increase theintensity of field, which is essen tial when the intensity of thecurrent dei creases toward zero, and the oscillation of the jet is to bekept up.

The invention relates to an improvement in the said rectifiers makingpossible a regulation down to zero of the intensity of the rectifiedcurrent.

According to the invent-ion a current is conducted from a specialauxiliary source of current througll the jet, which source of curmutatorestablishes connection between the said circuit and lthe electrode orelectrode'- parts of the rectifier during the period when this or theseare touched by the rectifying jet, whereas it interrupts this connectionduring the period in which the elect-rode (or the part in quest-ion or'the electrode) is not touched by the rectifying jet. Thus there isalways suliicient current fiowing in the recti fier jet to keep it inmotion, even if the current to be rectitied becomes small or is cut oil'entirely,

Figure l shows diagrammatically a component part of a rectifieraccording to the invention;

Fig. 2 shows diagrammatically a complete rectifier for rectii'ymg singlephase alternating current, using constant magnetic field and an auxiliarf source of alternating current;

for single phase alternating current using an alternating magnetic fieldand a single auxiliary source of direct current;

Fig. 4 shows a similar modification but using two separatesources ofauxiliary direct eurent;

Fig. 5 shows a modificatio -of a rectifier using two rectiying jets7twocorre'sponding constant magnetic fields and a single auxil- -.iarysource ot directI c'urrent, and

i Fig. 6 shows diagrammatically a rectifier for thi'ee phase alternatingcurrent using a revolving magnetic field and a single auxil-- iarysource ot' direct current.

The broad principle ot the invention appears rom Fig. l, which shows acomponent part of most of the above mentioned rectifiers. V designatesthe source of the alternating current, S designates the conductingrectifying jet, M a constant magnetic field the lines of force of whichare perpendicular to the plane of the paper, and designates an electrodeon one side limited by an insulating plate P, against the sharpened edgeof which thejet is directed when in a currentlesscondition. In this Fig.3 shows'diagiainmatically'a rectier position the jet is in conductiveconnection with the electrode E, part of the jet run-` ning down alongIthe oblique surface of the plate l). This apparatus is able'to sluit outfrom the workingconductor u, every other half period of the alternatingcurrent which the source ot' the alternating current. would sendlthrough this wire if the jet remained unlnoved in the position shown inthe drawing.

Asvexplaincd in the above named pending application the electrode E mustbe arranged at a distance from" the field M equal to an odd multiple of'the distance the parts ot the currentless jet would move during' a halt'period of the alternatingcurrent. The apparatus will then act in such amanner that' every other half period through interaction between thecurrent and the magnetic field M produces a wave on Ilhe `iet outward tothe right so that the striking` point of' the jet is a rried away fromthe electrode, and thc conductor (l, therefore is only passe'd by theother half periods.

ln order to keep up the motion of the parts ot' the jet necessary Yforthe rectification` independently otI the rectified current. a currentot' essentially the same nature as the rectified current flowing throughthe jet during` the i'ectification will have to be sent through the jet.ln the case here under considerationthere wil'llthus'have to be sent.through the jet a pulsating current with the same munber of periods asthe current delivered by the source of alternating current V and`r whatis of vessential importance, in phase with the same.'- Such a currentycan be, lroduced by a source" of alternating cui'- rent y,yvhich-isarrangedin a branch circuit including the terminal 'brjet S, and contactE. rfolkconnectthe point/I) with the electrode E b iiineans of apermanent closed wire wouldnot in'genei'al hev advisable. as insuclucase the; source of alternating cnrrent V would beysho'rtwirci'nted through this wire, and inthe. workingr conductor a norectified current would bel obtainable. cordinfjr to't'he inventiontherefore a kind ofI commutator or interrupter is used closing theconnection duringl 'the period in which the jet S touches the electrodelt). but interrupts the connection between the electrode and the pointat the moment when thc jet. S leaves the electrode. Such a corn mutatoris preferably made as a liquid jetl interruptor consisting ot a liquidjet s flowing'through a magnetic field m and strikincr an electrode cof' the same kind as the electrode E. The. electrode c can be adjustedtoward and from the field m until the jet .s strikes over thel edge ofthe insulatingplate y) at the same moment that the jets strikes over theedge of thc plate P. lt is understood that the pole tension for theauxiliary source of current o. v'. c., the

difference of potential between the points c and (l. must be in phasewith the pole tension of' the source V of the alternal in g current. orthe difference of potential between the points a and f. The distance otlthe electrode E from the field M is. as named'` assumed to be an oddmultiple ot' the distance through which the parts of' the jet. moveduring a halfl period of' th*4 alternating; current. and the distance ofthe electrode c from the field m must be fixed in a similar manner,which ot course does not. m an that the distances become alike, becausethe speed of the particles of the jets may differ. and another oddmultiple may be chosen for the distance passed b v the particles of thejet during one haltl period. Practicallyv the auxiliary apparatusconsisting,r of the jet s and they appurtenant parts can bc of lighterconstruction than thc corresponding parts ot' the rectifier proper asthe auxiliary ap paratus to work with but the very small etl'ectdemanded by the maintainingy of the oscillation ot the iet S. In orderto prevent the amplitude in a lighter jet from being too greatfthe.field m should simply be weakened. 'ith the same speed f'or theparticles of thc jets S and .s the intensity of the field 1n. shouldnormally be made as many times smaller than that ot' the 'field M as thecross section of the jet S is greater than that of the jet, lt may beremarked that the field ym must have a direction opposite to that ot'the field M. because the cur rent in the jet s is flowing' iu adirection opposite to that of the current in thc jet S.

It will now be. shown how the above explained principle can be used forthe various' practical modifications f'or rectifiers` of the, kind inquestion.

In the modification shown in Fig. 2 the jet S is to convey alternatingcurrent which is delivered by the source of current V. The jet passes aconstant field M and strikes a double electrode, the parts El and EL, ofwhich are separated b v means of an insulating plate. .\n auxiliarysystem is provided which has a jet a, similarto the jet S, one

terminal of which is so connected to source of' current V that aportion,7 V'v thereof furnishes sufficient current for.' the. auxiliarysystem. 'lhe jet .s strikes an electrode, the parts c1 and e: of whichare connected with the partsl El and E2, respectively7 as shown. Thefield m is a const-ant field. The disstance from thc electrode c1, e2from the field Imy is adjusted in such a manner that the strikingr pointof the jet s passes over from the electrode c. to the electrode a2 atthe same time that the jet S passes from the electrode E, to theelectrode Ei., and vice In this modification the working circuit orresistance is divided. each of the two directions of' current; flowingthrough its working resistance R1 and R2 respectively.

It-japbears from the above that the current ,in the j e-t S due to thesource V of alternatsists of two halves V1 and V2. The field M is herean alternating field fed with current from the same generator whichdelivers the current to be rectified. Through the jet S fiows in thismodification the rectified current proper which has the character of anunbroken direct current. The auxiliary current which is sent through thejet s will then have to be a direct current also. This latter isapprcpriately taken from a storage cell B. The alternating field m isfed with the same current as the alternating field M, which currentY isappropriately delivered by the source of current V1, V2 as indicated in.the dra-wing. The system containing the jet is presumed to beadjusted-for normal rectifying. The distance of the electrodes el, c2from the field m is adjusted in such a manner that the striking point ofthe jet s passes over from the elect-raide 'el to the electrode e2 at`the same moment that the jet F passes over from the electrode el to theelectrode E2. Instead of, 4as shown` arranging the storage cell 'Bbet-Ween the points g and It, the same may be inserted between thepoints g and Finally a storagecell B1 and B2 may be inserted in each ofthe two wires nl and n.2 which connect the electrode parts in question,as shown in F ig. si, which represents a similar rectifier.

In Fig 5 is shown a rectifier composed.

of two syste-ms similar to that shown in Fig. l. The working conductor ab is here .undivided7 and during the rectifying direct current isconstantly flowing through the same. The pulsating currents which are'here to be. produced in the two jets S1 and S2, may be taken from astorage4 cell B, which, as shown is inserted in a circuit containing theauxiliary jet s common :for the twoljets'S1 and S2. .1nd the systemwhich effects the maintaining of the connection in this manner betweenthe source B of auxiliary current and the jets Sl and S2 may be of thekind shown in Fig. 3. T he winding for the magnet producin the magneticfield el, e2 in which thc striking point of the jet a passes over fromthe part el to the part e2 contemporarily with the jet S1 leavingjthepart E1 and the jet S2 entering the part E2. The pulsating current whichin this apparatus fiows from the source of current B through the jets S1and S2 will not have the same shapev of curve as that delivered by thesource of current V1,'V2 l but it will have the same frequency and be inphase with the same', which is all that is demanded for maintaining thenecessary mot-ion of the jets Sl and S2. also when the intensity of therectified current decreases to zero or to a low value.v

Finally Fig. 6 shows diagrammatically a rectifier with rotating fieldfor cases citeren the number of the phases is three. The rwindings ofthe generator' are designated by V1. V2 and V3. The coils produce ingthe rotating field actuating the jet are designated by M1, M2 and M3,and the part-s of the electrodes by El, E2, and E3.

The auxiliary system consists of'a jet 3 passing a rotating fieldproduced by the coils m1, m2 and m3, and striking an electrodeconsisting of the mutually insulated sectors el, e2 andA e3. The variousparts are connected by `wires as indicated. During the rectification, inthe jet S flows a direct current. and the auxiliary current isappropriately taken from a storage cell B inserted between the two jetsS and s, which in the figure are represented as points. The field coilsm1, mz-and m3 are preferably inserted in series with the coils M1, M2and M3, respectively, as indicated.

The auxiliary system not only enables regulation of the rectifiedcurrent down to zero but makes possible the rectication of relativelyhigh tension current by relatively small intensities of current. In thesystem shown in Fig. 3 and in multiphase systems with rotating field theauxiliary system may be used as starting means, and it does away withthe drawback otherwise attached to the said kinds of rectifiers that thedirection of the rectified :urrent is a matter of chance. lVhen therectifiers are started by means of auxiliary systems, the rectifiedcurrent in the jet will always get the same direction as the auxiliarycurrent.

Having thus fully described my invention,

I claim as new and desire to secure by Letters Patent- 1. Thecombination of a liquid jet rectifier for alternating currentscomprising a conducting jet, and means for keeping said jet in motionduring all variations in the strength of the rectified current,including an auxiliary circuit shunted across the jet.

mis fed with current trom the same genera- :2. The combination of aliquid jet rectitor which delivers the current to be rectified. It isunderstood that it will be possible to find one or more positions of theelectrode fier for alternating currents comprisinga conducting jet, andmeans for keeping said jetin motion duringgall variations in the l/ I 'xstrength of the rectified current, including an auxiliary circuit andconducting sliunted across the first named jet.

il. The combination of a liquid jet rectifier for alternating currentscomprising a conducting jet and a plurality of electrodes normalyimpinged upon by said jet when no rectified current is passing, andmeans for keeping said jet in motion during all variations in thcstrength of the rectified current, said means including an auxiliarycircuit shunted across the jet and electrodes.

4.. The combination of a liquid jet rectifier for alternating currentscomprising a conducting jet, and means for keeping said jet in motionduring all variations in the strength of the rectified current,including an auxiliary circuit. and conducting jet -shunted across thefirst named jet, and means for causing said auxiliary jet to more insynchronism with the rectifier jet.

5. The combination of' a liquid jet rectifier for alternating currentscomprising a conducting jet and a plurality of electrodes normallyiinpinged upon by said jet when no rectified current is passing, andmeans for keepingsaid jet in motion during all variations in thestrength of the rectified current, said means including an auxiliarycircuit sliunted across the jet and electrodes,

rents, comprisinga conducting liquid jet, f

means for producing a magnetic field crossed by the said jet, and meanscomprising an electrode for passing an electri l current through thesaid jet, the said field and current being of such a character as toproduce a periodical force acting on the said jet, a crcuit comprisingan auxiliary source of' current a commutator consisting of an auxiliaryliquid jet, means for producing a magnetic field coacting with the saidauxiliary jet 'to produce oscillations of the same, and an auxiliaryelectrode connected with the first named electrode, the said commuta-torbeing adapted to automatically establisli connection between the saidcircuit. f

and the first named electrode during the periods in which the same istouched by the said jet, and to interrupt the said connection during theperiods in which the said electrode is not toucli'ed by the said jet.

In testimony whereof I have affixed my signature.

JULIUS FREDERIK GEORG POUL HAPJMANN.

